The prostate is almost invariably the site of benign and malignant proliferative changes in aging males. Benign prostatic hypertrophy (BPH) is the most common non-malignant proliferative abnormality of internal organs. A high percentage of these age-related growth disorders develop into malignancies. As a result of this, adenocarcinoma of the prostate represents the most common malignancy in American males and is the second leading cause of cancer deaths in men.
A useful method in the diagnosis of prostate cancer is determining the level of prostate specific antigen (PSA) in the blood. PSA is a glycoprotein secreted by the prostate gland. However, the PSA test has limitations of sensitivity and selectivity: In general, levels above 4 ng/ml are suggestive of cancer and levels above 10 ng/ml are highly suggestive. However, many individuals with elevated levels do not have prostate cancer, but exhibit benign prostatic hypertrophy. Conversely, many persons with prostate cancer have normal PSA levels at the time of diagnosis. Therefore, prostate cancer markers with greater sensitivity and selectivity for prostate cancer would be useful for, among other things, the diagnosis of prostate cancer.